Reserved Addresses and Lease Type

Addresses can be reserved by manually assigning them
to particular clients. A reserved address can have a permanent or dynamic
lease associated with it. When a reserved address is assigned a permanent
lease:

The address can be allocated only to the client that is bound
to the address

The DHCP server cannot allocate the address to another client

The address cannot be reclaimed by the DHCP server

If a reserved address is assigned a dynamic lease, the address can be
allocated only to the client that is bound to the address, but the client
must track lease time and negotiate for a lease extension as if the address
were not reserved. This allows you to track when the client is using the address
by looking at the network table.

You cannot create reserved addresses for all the IP addresses during
the initial configuration because they are intended to be used sparingly for
individual addresses.